Learn About Insulinoma
An insulinoma is a tumor in the pancreas that produces too much insulin.
Insulinoma; Islet cell adenoma; Pancreatic neuroendocrine tumor; Hypoglycemia - insulinoma
The pancreas is an organ in the abdomen. The pancreas makes several enzymes and hormones, including the hormone insulin. Insulin's job is to reduce the level of sugar (glucose) in the blood by helping sugar move into cells.
Most of the time when your blood sugar level decreases, the pancreas stops making insulin to make sure that your blood sugar stays in the normal range. Tumors of the pancreas that produce too much insulin are called insulinomas. Insulinomas keep making insulin, even when it's not needed, and can make your blood sugar level too low (hypoglycemia).
A high blood insulin level causes a low blood sugar level (hypoglycemia). Hypoglycemia may be mild, leading to symptoms such as anxiety and hunger. Or it can be severe, leading to seizures, coma, and even death.
Insulinomas are very rare tumors. They usually occur as single, small tumors. But there can also be several small tumors.
Most insulinomas are non-cancerous (benign) tumors. People with certain genetic disorders, such as multiple endocrine neoplasia type I, are at higher risk for insulinomas.
Symptoms are most common when you are fasting or skip or delay a meal. Symptoms may include:
- Anxiety, behavior changes, or confusion
- Clouded vision
- Loss of consciousness or coma
- Convulsions or tremor
- Dizziness or headache
- Hunger between meals; weight gain is common
- Fast heart rate or palpitations
- Sweating
Surgery is the usual treatment for insulinoma. If there is a single tumor, it will be removed. If there are many tumors, part of the pancreas will need to be removed. At least 15% of the pancreas must be left to produce normal levels of enzymes for digestion.
In rare cases, the entire pancreas is removed if there are many insulinomas or they come back after surgery. Removing the entire pancreas leads to diabetes because there is no longer any insulin being produced. Insulin shots (injections) are then required.
If no tumor is found during surgery, or if you can't have surgery, you may get the medicine diazoxide to lower insulin production and prevent hypoglycemia. A water pill (diuretic) is given with this medicine to prevent the body from retaining fluid. Octreotide is another medicine that is used to reduce insulin release in some people.
Guillaume Nicolas practices in Basel, Switzerland. Mr. Nicolas is rated as an Elite expert by MediFind in the treatment of Insulinoma. His top areas of expertise are Insulinoma, Neuroendocrine Tumor, Medullary Thyroid Carcinoma, and Pancreatic Cancer.
Beat Gloor practices in Bern, Switzerland. Gloor is rated as an Elite expert by MediFind in the treatment of Insulinoma. Their top areas of expertise are Insulinoma, Pancreatic Cancer, Multiple Endocrine Neoplasia Type 1, Pancreaticoduodenectomy, and Hepato-Pancreato-Biliary Surgery.
Maarten Brom practices in Nijmegen, Netherlands. Mr. Brom is rated as an Elite expert by MediFind in the treatment of Insulinoma. His top areas of expertise are Insulinoma, Type 1 Diabetes (T1D), Pancreatic Cancer, Islet Cell Transplantation, and Gastric Bypass.
In most cases, the tumor is non-cancerous (benign), and surgery can cure the disease. But a severe hypoglycemic reaction or the spread of a cancerous tumor to other organs can be life threatening.
Complications may include:
- Severe hypoglycemic reaction
- Spread of a cancerous tumor (metastasis)
- Diabetes if the entire pancreas is removed (rare), or food not being absorbed if too much of the pancreas is removed
- Inflammation and swelling of the pancreas
Contact your health care provider if you develop any symptoms of insulinoma. Seizures and losing consciousness are an emergency. Call 911 or the local emergency number right away.
Summary: Hypoglycemia is the term used to refer to lower than normal levels of blood sugar. This study will continue to research the causes of hypoglycemia. Patients involved in the study will be admitted to the Clinical Center of the National Institutes of Health and undergo tests for evaluating blood sugar. Patients will be required to refrain from eating for a set period of time and will undergo blood t...
Summary: Multiple Endocrine Neoplasia type 1 (MEN1) is an autosomal dominant disease with a high degree of penetrance (\>80% of patients). It is caused by the presence of the MEN1 mutation located on chromosome 11q13. The prevalence of this mutation is estimated at approximately 1/30,000. This hereditary syndrome is characterized by the presence of tumours of the endocrine system (adenoma of the parathyroi...
Published Date: July 21, 2024
Published By: Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. Editorial update 01/17/2025.
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Strosberg JR, Al-Toubah T. Neuroendocrine tumors. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 34.